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KA24E Timing Chain Rattle on Start up


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The KA24E is notorious for grinding up cam chain guides every 80K. The plastic coating on the guides peels off and ends up in the sump. Replacement is all you can do. But first, take the valve cover off and inspect it for wear. You may be surprised to see bare metal. I blame this on simply being too god damn cheap. The L and Z series had a robust double chain and guide width. "well the never broke so why don't we run a single chain? and save the money"

 

The KA engine I tore down had good chain guides because they had been replaced. Found the old guide plastic in the bottom of the oil pan...

 

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The tensioner is spring loaded and does have a small boost from oil pressure. I worked it out once to about 8 pounds with a 50 PSI pump pressure. The oil is mostly for lubrication. What oil you using? I run 15w40 Rotella T4. This will boost the start up pressure on the chain tensioner.

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You can get the upgraded timing chain kit for about $100, seen it for less too, metal guides with a coating of some fancy rubber like plastic, you can also get a self adjusting tensioner that is self adjusting as things wear and the chain loses tension in order to eliminate chain slack, Google self adjusting tensioner for KA24e

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  • 4 years later...

Is there any ratcheting tensioner less than $150.00.............???
They were 130, now 150 when I think about finally getting one.

From the way I understand the problem, as the slider wears, if the tensioner does not
keep taking up the space and has is has the ability to recess,  you could get chain slap.
I have had people tell me they really like theirs.
Has anyone tried others?
Are there others? I haven't had much luck finding other units




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The coatings on the guides wear and come off. They need replacing every 80k or so. The tensioner is part of the slack side guide, swinging the top over against the chain to absorb slop. The bottom is hinged. I had a KA apart once and the guides had been replaced.... all the old guide rubber parts were in the oil pan. There's no ratcheting, it uses spring pressure and some oil pressure to bear against the chain. If the 'rubber' coating is gone it will make noise.

 

RMrppYE.jpg

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Yeah, that is the problem with the KA
The tensioner works off oil pressure and will rattle on startup waiting on the oil to arrive, even with the check valve.
The ratchet adjuster never goes so far back to let it close all the way and compensates for wear also.
The only design I know that will do that. Chain slap is what breaks the left side slider.
I am going to replace the chain and it will be the last one I put in it.
If I am going to drive it, I don't want chain slap on  startup

 

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While oil pressure is supplied to the tensioner it's mostly the massively strong spring inside that pushes the entire slack side guide out against the chain. I worked out the oil pressure once for the L series tensioner. At 55 PSI the area of the tensioner ads less than 8 pounds of outward force

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on the ka-t.org forums the suggest going to the OSK timing chain kit due to heavy duty guides, or going with oem if they are still available. also the ratcheting tensioner guide is an added security

link bellow is the guy that provides them 

https://www.martin-industries.net/product-page/nissan-ka24e-self-adjusting-tensioner

 

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Yeah, that was my question,
IS the Martin Industries the only ratcheting KA chain adjuster on the market?
It is the only one that makes sense to buy, but pricey compared to ones for other engines.
It will adjust itself until the chain is done & never really relies on Oil pressure on start up.
with as little as a drive and me being 60, a new chain will last the rest of my life.
They are $150.00 now........

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The tensioner does have a skookum strong spring behind it, so it's not like the guide backs off when the engine is off. The chain is always under tension on the 'slack' side. If there is noise on start up it's probably the coatings on the guides have worn or peeled off and it's metal to metal.

 

I'm of the opinion that the oil supply is just to lubricate the tensioner. Like I said earlier I measured an L series tensioner inside diameter and at 55 PSI oil pressure the extra outward push of the oil was only 7 or 8 pounds. If this was critical the spring could simply be made 7 or 8 pounds stiffer.

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